Fix both 10.8 Mountain Lion and 10.9 Mavericks support

Changes:

 - Update the "go" script to use more of the Homebrew original
 - Testing the "go" script in Travis
 - Support for both 10.8 Mountain Lion and 10.9 Mavericks for the "go" script
 - Rework the "kitchenplan" script to use a lot of the Homebrew go script methods
 - Support for both 10.8 Mountain Lion and 10.9 Mavericks for the "kitchenplan" script
 - Added a ping to Google Analyics to track the usage of Kitchenplan
Merge pull request #39 from kitchenplan/feature/mavericks_AND_mountainlion_support

Fix both 10.8 Mountain Lion and 10.9 Mavericks support